1. Field of the Invention
This invention relates to a process for preparing a tufted carpet which has a nonwoven fabric secondary backing. More particularly, the invention concerns the embossing of the secondary backing after the secondary backing has become an integral part of the carpet. Such embossing provides a more stretchable carpet for easier installation.
2. Description of the Prior Art
Processes for manufacturing tufted carpets are well-known in the art. In such processes, a woven or a nonwoven fabric, called a primary backing, is tufted with yarns which form the face pile of the carpet. A latex or a melt adhesive, often referred to as a "back-size" is then applied to the back of the primary backing to anchor the base of the pile yarn tufts in the primary backing. Usually, a secondary backing is then laminated to the back-sized surface of the primary backing. The process can also include additional steps such as dyeing, shearing, heat setting, and so forth.
A process similar to the ones just described is disclosed in U.S. Pat. No. 3,322,607. This patent also discloses the use of a secondary backing in the form of a self-bonded nonwoven fabric made from thermoplastic fibers. Embossed secondary backings of this type are disclosed in U.S. Pat. No. 3,414,458. Note that the embossing is carried out before the secondary backing is attached to the back-sized, tufted primary backing.
Tufted carpets made by the above-described processes have been widely used throughout the world. Generally, such carpets are installed with an initial stretch of at least about 0.2%, preferably about one-half to one percent when used wall-to-wall in large rooms. This initial stretch is desired to avoid carpet-distortion problems induced by subsequent temperature and humidity changes in the room. However, the present inventor found that when the secondary backing of the tufted carpet was a bonded nonwoven fabric, especially one made from filaments of polypropylene or polyester, the completed carpet frequently was stiffer than desired for easy wall-to-wall installation in large rooms and often required the use of power stretchers rather than knee-kick stretchers to obtain the desired initial stretch.